Airbag device

ABSTRACT

An airbag device for stably controlling gas discharge and restraining an occupant in a vehicle. A first vent hole, for discharging gas from the airbag, is formed in a portion of the airbag, and one end of a tubular discharge restricting member is connected to the first vent hole. Once the airbag is inflated and deployed to a predetermined extent or more, the first vent hole is closed by the discharge restricting member. Prior to deployment, at least a portion of the airbag is folded in a bellows shape to form a folded portion. The connecting portion between the discharge restricting member and the first vent hole is positioned in a trough portion of the folded portion. The other end of the discharge restricting member is stored so as to face the outer side and not to protrude beyond an outer edge of the folded portion.

BACKGROUND

1. Field of the Invention

The present invention relates to an airbag device that restrains anoccupant in a vehicle. More specifically, the present invention relatesto an improvement of an airbag device having a vent control mechanismthat uses a tubular member.

2. Description of the Related Art

Examples of an airbag device include a driver's seat airbag devicestored in the central portion of a steering wheel (handle), an assistantdriver's (passenger's) seat airbag device stored in an instrument panel(dashboard), a curtain airbag device deployed from the vicinity of aroof rail so as to cover a window, a side airbag device incorporatedinto a seat, and the like. The airbag device is designed to protect anoccupant from an impact using an airbag to absorb and mitigate theimpact in the event of a crash.

However, general airbag devices have such a structure that an airbag isinstantly inflated by high-pressure gas jetted from an inflator and isdeployed in a predetermined direction. When an occupant or the likecollides with an airbag during an initial stage of inflation anddeployment, a serious impact during the inflation may act on theoccupant or the like and the potential for injury from the airbag mayincrease. In order to prevent this, various vehicle airbag devices havebeen proposed.

In one vehicle airbag device, a plurality of inflators that mitigate animpact acting on an occupant or the like is provided so as to detect inadvance the occupant or the like approaching an airbag in the initialstage of inflation and deployment of the airbag and to adjust theinflation pressure of the airbag accordingly. In the initial stage ofinflation and deployment, high-pressure gas is jetted from one inflator.After that, the high-pressure gas is jetted from the plurality ofinflators. In this way, the airbag is allowed to be deployed in apredetermined shape.

As another airbag device, initial pressure during inflation of theairbag is sufficiently high, but the gas discharged from a vent hole isdistributed to a wide range of areas. In such an airbag device, atubular nozzle is extended from the vent hole formed in the airbag, andthis nozzle is stored in the airbag when the airbag is in a foldedstate. Due to this, during the initial stage of inflation of the airbag,the nozzle is pressed against the inner wall of the airbag due tointernal pressure of the airbag, and the vent hole is closed. Once aninitial internal pressure is attained, as well as when the internalpressure of the airbag becomes higher than predetermined pressure, thenozzle is pushed outside the airbag from the vent hole and spreads in atubular form to distribute the gas discharged from the vent hole in awide range of areas while shaking.

In the airbag configured to detect in advance the occupant or the likeapproaching the airbag in the initial stage of inflation and deploymentof the airbag, it is necessary to adjust an opening size of the venthole formed in the airbag using electromagnetic switch means or to equipdetection means for detecting the occupant or the like. Thus, there is aproblem in that the airbag device becomes complex and expensive.Moreover, in an airbag having a plurality of inflators, it is difficultto adjust the ignition time of the inflators, and the inflation pressureof the airbag in the initial stage of inflation is not sufficient. Thus,there is a problem in that sufficient impact absorbing power is notobtained.

Therefore, there is a demand for an airbag device capable of adjustingthe internal inflation pressure of an airbag according to the stage ofinflation and deployment of the airbag. To meet such a demand, forexample, Japanese Patent Application Publication No. 2008-207579proposes a structure in which one end of a flexible tubular member isconnected to a vent hole and the tubular member is pulled into an airbagin response to inflation of the airbag to restrict gas discharge of thevent hole. In such a structure, a tubular control member is extended tothe outside of the airbag in the initial stage of inflation anddeployment of the airbag. When an occupant or the like comes intocontact with an occupant restraint surface, a portion of high-pressuregas in the airbag is discharged outside from the vent hole and theinternal inflation pressure of the airbag decreases. Thus, even when theoccupant or the like approaches the airbag in the event of a vehiclecrash and the occupant or the like comes into contact with the airbagduring the initial stage of inflation and deployment, it is possible toreliably restrain the occupant or the like while decreasing repulsiveforce acting on the occupant or the like. Moreover, in a normal statewhere the occupant or the like is away from an inflated and deployedairbag, the control member is pulled into the airbag. Thus, it ispossible to prevent the gas from being discharged from the vent hole. Asa result, the airbag can be inflated and deployed by effectivelyutilizing the pressure of gas jetted from the inflator and can providesufficient impact absorbing power.

However, in the structure in which the tubular member is connected tothe vent hole, there is a problem in that the gas discharge performance(gas discharge volume) of the vent hole varies depending on how theairbag and the tubular member are folded.

SUMMARY

The present invention has been made in view of the above problems, andan object of the present invention is to provide an airbag devicecapable of stably controlling gas discharge.

In order to attain the object, the present invention provides an airbagdevice that restrains an occupant in a vehicle by inflating anddeploying an airbag, wherein a first vent hole for discharging gasinside the airbag is formed in a portion of the airbag, one end of atubular discharge restricting member is connected to the first venthole, the first vent hole is configured to be closed by the dischargerestricting member when the airbag is inflated and deployed to apredetermined extent or more. At least a portion of the airbag is foldedin a bellows shape to form a folded portion, a connecting portionbetween the discharge restricting member and the first vent hole ispositioned in a trough portion of the folded portion, and the other endof the discharge restricting member is stored to face the outer side andnot to protrude outside an outer edge of the folded portion.

Here, the trough portion of the folded portion is not limited to thecomplete end of a concave portion, but may be positioned slightly on theouter side in a range where the discharge restricting member is not benthalfway. Moreover, “not to protrude” means a case where the other endprotrudes slightly within a range where the distal end of the dischargerestricting member is not bent or gas discharge is not prevented toomuch in the initial stage of deployment as well as a case where theother end never protrudes.

Moreover, the “outer side” in the expression that the other end of thedischarge restricting member faces the “outer side” without protrudingtoward the “outer side” than the outer edge of the folded portioncorresponds to the peak portion (the opposite of the trough portion) ofthe folded portion when the airbag is in the folded state, andliterally, corresponds to the outer side of the airbag surface when theairbag is in the deployed state. The left side of FIGS. 4A and 4B is theouter side.

According to the present invention having such a configuration, thetubular discharge restricting member does not protrude toward the outerside of the airbag in the stored state (in the non-deployed state of theairbag). Due to this, the discharge restricting member can maintain astate of straightly extending toward the outer side without being bent,the first vent hole can be quickly put into an open state in the initialdeployment state of the airbag. Thus, it is possible to realize stablegas discharge control. That is, it is possible to stably control theclosing timing and the gas discharge volume of the first vent hole(safety vent).

The discharge restricting member may maintain a state of extendingtoward the outer side of the airbag without being bent when the airbagis stored without being deployed. Due to such a structure, the dischargerestricting member can easily maintain a stable attitude without beingbent by being interposed between the upper and lower airbags.

The airbag device may further include a tether of which one end isconnected to the discharge restricting member and the other end isconnected to the inside of the airbag, and the discharge restrictingmember is closed by being pulled into the airbag by the tether when theairbag is deployed to a predetermined extent or more. Due to such aconfiguration, it is possible to control the opening and closing of thedischarge restricting member with a simple structure.

A second vent hole that is always open may be formed in the airbag inaddition to the first vent hole. Due to such a structure, it is possibleto increase an adjustment range in which the internal pressure of theairbag is controlled. That is, when an occupant abnormally approachesthe airbag, it is possible to further decrease the internal pressure ofthe airbag in the initial stage of deployment and to decrease the injurylevel of the occupant.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating a deployed state of an airbagdevice according to an embodiment of the present invention;

FIGS. 2A to 2C are diagrammatic illustrations of the state where theairbag according to the embodiment of the present invention is folded,in which FIG. 2A is a plan view, FIG. 2B is a side view, and FIG. 2C isa cross-sectional view along line A-A of FIG. 2B;

FIG. 3 is an enlarged perspective view illustrating the structure of amain part (discharge restricting member) of the airbag according to theembodiment of the present invention; and

FIGS. 4A and 4B are explanatory diagrams illustrating a folded state ofthe airbag according to embodiments incorporating the principles of thepresent invention.

DETAILED DESCRIPTION

Preferred embodiments of the present invention will be explained next indetail by way of an assistant driver's (passenger's) seat airbag devicewith reference to accompanying drawings. In the description and thedrawings, elements having substantially the same function andconfiguration are denoted by identical reference numerals, and arecurrent explanation thereof will be omitted. Elements that are notdirectly related to the present invention are omitted in the drawings.

The present invention relates to an airbag device that restrains anoccupant in a vehicle by inflating and deploying an airbag 10. Thepresent invention can be applied to other airbag devices, such as adriver's seat airbag device, as well as an assistant driver's seatairbag device. In FIG. 1, a first vent hole 14 that discharges gas frominside the airbag 10 is formed in a portion of a side surface of theairbag 10 on a vehicle interior side. If two of the first vent holes 14are formed on both left and right side surfaces of the airbag 10, onefirst vent hole of the airbag on a vehicle exterior side can be formedat a position symmetrical to another first vent hole on the vehicleinterior side when seen from the occupant side. Here, the “vehicleexterior side” means a side close to the door as seen from the occupantside when the airbag is an assistant driver's seat airbag or a driver'sseat airbag, and the “vehicle interior side” means the opposite side.

The first vent hole 14 is configured to be opened and closed accordingto a deployment state of the airbag 10, and the details thereof will bedescribed hereafter. A second vent hole 12, as an always open hole, isalso formed in the airbag 10 in addition to the first vent hole 14. Thesecond vent hole 12 may be formed near the center of a side surface ofthe airbag in the deployed state. Moreover, the first vent hole 14 isformed on the front side (inflator side) of the second vent hole 12.

As illustrated in FIGS. 2B and 2C, an inflator 20 that generatesinflation gas is disposed inside the airbag 10. Referring to FIG. 1, theinflator 20 is disposed further closer to the front side of the firstvent hole 14. In FIG. 1, the “front side” indicates a vehicle advancingdirection, and the “rear side” indicates a vehicle cabin side (occupantside).

One end of a tubular discharge restricting member 16 is connected to thefirst vent hole 14. The discharge restricting member 16 can be formed ina cylindrical form using the same fabric as the airbag 10, for example.In a state where the airbag 10 is not fully deployed, as illustrated inFIG. 3 and FIGS. 4A and 4B, the other end of the discharge restrictingmember 16 is extended to the outside of the airbag 10.

Returning to FIG. 1, a tether 18 is connected to the dischargerestricting member 16. One end of the tether 18 is connected to thedischarge restricting member 16, and the other end is connected near thebottom of the airbag 10. In the connection portion between the tether 18and the airbag 10, it is preferable that, during normal deployment,tension is generated in the tether 18 and gas discharge is restricted toclose the first vent hole 14. Moreover, it is preferable that, even whenthe airbag 10 restrains an occupant seating at a normal seatingposition, tension is generated in the tether 18 and gas discharge isrestricted to close the first vent hole 14. In this way, it is possibleto appropriately control the opening and closing of the first vent hole14.

Referring to FIG. 3, the other end (free end) of the dischargerestricting member 16 is turned down back over itself and sewn to form abag-shaped sewn portion 22. An elastic portion 18 b of the tether 18 isinserted in the bag-shaped sewn portion 22, and a connecting portion 18a of the tether 18, connected to the airbag 10 and is connected to theelastic portion 18 b. When the airbag 10 is deployed to a predeterminedextent or more, the connecting portion 18 a which is normally loosepulls the elastic portion 18 b, and the discharge restricting member 16is pulled into the airbag 10 and is closed in a pouch shape.

An opening such as a slit is formed in a portion of the bag-shaped sewnportion 22 so that an end portion (the connecting portion 18 a) of thetether 18 passes through the opening. This is similar to the structureof a trouser of such a type that a waist part is fastened by a band. Thetether 18 may be formed of one tether and may be formed by joining aplurality of tethers. For example, when the tether 18 is formed of onetether, an end portion of the elastic portion 18 b that is not connectedto the connecting portion 18 a may be fixed by sewing or the like to anintermediate portion of the bag-shaped sewn portion 22.

FIGS. 2A to 2C are diagrams illustrating the state where the airbag 10is folded, in which FIG. 2A is a plan view, FIG. 2B is a side view, andFIG. 2C is a cross-sectional view along line A-A of FIG. 2B. FIG. 4Aalso illustrates a folded state of the airbag 10. When the airbag 10 inthe folded state is seen from above, bellows-shaped folded portions 10 aand 10 b are formed at opposite end portions as illustrated in FIG. 2A.The base (that is, the first vent hole 14) of the discharge restrictingmember 16 (two oppositely positioned discharge restricting member 16 a,16 b been seen in FIGS. 2A to 2C) is positioned in the trough portions(see FIG. 4) of the folded portions 10 a and 10 b of the airbag 10.Here, the trough portions of the folded portions 10 a and 10 b are notnecessarily limited to the complete ends of concave portions asillustrated in FIG. 4A, but the trough portions may be positionedslightly on the outer side of the trough portion in a range where thedischarge restricting member 16 (16 a, 16 b) is not bent halfway orfolded upon itself, as seen in FIG. 4B. Moreover, the outer end ordistal portion of the discharge restricting member 16 (16 a, 16 b) isdisposed so as not to protrude toward the outer side more than the outeror lateral ends of the folded portions 10 a and 10 b. Here, “so as notto protrude” means a case where the outer end portion may protrudeslightly within a range where the distal end is not bent or folded over,or gas discharge is not prevented too much in the initial stage ofdeployment, as well as a case where the outer end portion of thedischarge restricting member 16 (16 a, 16 b) never protrudes beyond thelateral ends of the folded portions 10 a and 10 b. However, it isobvious that excellent attitude stability is obtained when the outer endportion does not protrude completely.

In the present embodiment, when the airbag 10 is in a stored state(non-deployed state), although the tubular discharge restricting member16 (16 a, 16 b) extends toward the outside of the airbag 10, since thedischarge restricting member 16 (16 a, 16 b) does not protrude from theouter edge of the airbag 10, the discharge restricting member 16 (16 a,16 b) can maintain a state of straight extension without being benthalfway or folded over on itself (see FIGS. 4A and 4B). Due to this, thefirst vent hole 14 can be quickly put into an open state in the initialdeployment stage of the airbag 10 and the gas discharge resistance isminimized. Thus, it is possible to realize stable gas discharge controlin the initial stage of deployment. Moreover, since the dischargerestricting member 16 (16 a, 16 b) is interposed between the upper andlower folded portions 10 a and 10 b, the discharge restricting member 16(16 a, 16 b) can ideally maintain the straight (flat) state.

In the present embodiment, when the inflator 20 operates, the airbag 10folded in the state illustrated in FIGS. 2A to 2C starts to be deployed.Here, when an occupant is positioned close to the airbag 10, the airbag10 comes into contact with the occupant in the initial stage ofdeployment. In this case, the tether 18 is not fully extended, thedischarge restricting member 16 (16 a, 16 b) is extended outside theairbag 10, and the first vent hole 14 maintains an open state. Thus, theinternal pressure of the airbag 10 decreases, and the impact on theoccupant is mitigated. When the occupant is seating at a normal seatingposition, the airbag 10 is quickly deployed, the tether 18 is fullyextended and pulled taunt, the discharge restricting member 16 (16 a, 16b) is pulled into the airbag 10 by the tether 18, and the first venthole 14 is quickly closed to create a full deployment state at an earlystage so that the occupant can be quickly restrained. In the presentembodiment, by appropriately controlling the storage attitude of thedischarge restricting member 16 (16 a, 16 b), it is possible to stablycontrol the closing timing and the gas discharge volume of the firstvent hole 14 (14 a, 14 b).

While the embodiment of the present invention has been described, thepresent invention is not limited to the embodiment, and various changescan be made within the scope of the technical spirit described in theclaims.

I/we claim:
 1. An airbag device for restraining an occupant in the cabin of an automotive vehicle, the airbag device comprising: an airbag coupled to an inflator, the inflator configured to cause inflation and deployment of the airbag, at least one first vent hole defined in the airbag to exhaust inflation gas from inside the airbag; an exhaust control portion having a base and a distal end, the base of the exhaust control portion being connected about the first vent hole and the exhaust control portion extending outwardly from the airbag; in a non-deployed configuration, the airbag having folded portions defining troughs and peaks, the troughs being located inwardly of the non-deployed configuration and peaks defining an outer side of the non-deployed configuration, the base of the exhaust control portion being located at one of the troughs of the non-deployed configuration and the distal end of the exhaust control portion being located toward the outer side of the non-deployed configuration.
 2. The airbag device of claim 1, wherein the distal end of the exhaust control portion is adjacent to the outer side of the non-deployed configuration.
 3. The airbag device of claim 1, wherein the exhaust control portion is tubular in shape.
 4. The airbag device of claim 1, wherein, in the non-deployed configuration of the airbag, the exhaust control portion extends linearly from the base to the distal end.
 5. The airbag device of claim 1, wherein, in the non-deployed configuration of the airbag, the exhaust control portion extends in a straight manner from the base to the distal end.
 6. The airbag device of claim 1, wherein, in the non-deployed configuration of the airbag, the exhaust control portion extends along a straight line from the base to the distal end.
 7. The airbag device of claim 1, wherein, in the non-deployed configuration of the airbag, the exhaust control portion extends outwardly from the base to the distal end.
 8. The airbag device of claim 1, wherein, in the non-deployed configuration of the airbag, the exhaust control portion extends from the base to the distal end without folds being formed between the base and the distal end.
 9. The airbag device of claim 1, wherein the exhaust control portion is configured to close off the first vent hole upon the airbag inflating and deploying above a predetermined volume.
 10. The airbag device of claim 1, further comprising a second vent hole defined in the airbag, the second vent hole being permanently in an open configuration to exhaust inflation gas from inside the airbag.
 11. The airbag device of claim 1, wherein a tether is connected between the airbag and the exhaust control portion.
 12. The airbag device of claim 11, wherein the tether is connected to the distal end of the exhaust control portion.
 13. The airbag device of claim 11, wherein the tether extends through the first vent hole.
 14. The airbag device of claim 11, wherein a portion of the tether encircles the distal end of the exhaust control portion.
 15. The airbag device of claim 14, wherein the portion of the tether encircling the distal end of the exhaust control portion is configured to draw closed the distal end of the exhaust control portion.
 16. The airbag device of claim 11, wherein the tether has a length that is less than an unrestrained length from the first vent hole to an attachment point of the tether to the airbag upon full inflation and deployment of the airbag by the inflator, whereby the exhaust control portion is drawn by the tether through the first vent hole into the airbag when the airbag is inflated and deployed above a predetermined volume.
 17. The airbag device of claim 11, wherein, in the non-deployed configuration of the airbag, the exhaust control portion extends from the base to the distal end without folds being formed between the base and the distal end.
 18. The airbag device of claim 11, wherein, in the non-deployed configuration of the airbag, the exhaust control portion extends outwardly from the base to the distal end.
 19. The airbag device of claim 11, wherein the distal end of the exhaust control portion is adjacent to the outer side of the non-deployed configuration.
 20. The airbag device of claim 11, wherein the tether extends through the exhaust control portion. 